update to understanding lighting

# 1 10-03-2005 , 03:05 AM

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Hi there,
Well after practicing for awile, here is my update on understanding lighting. Also I would like your opinions on it. I know it doesn't look that great but I could use your help with your opinions.

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# 2 10-03-2005 , 03:24 AM

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decay is your friend, it looks like its lacking some decay
lower the decay and crank the intensity a bit and play with that and you might find some better results

it looks like the lamp is giving off too much light, and is lighting the entire room a bit too well.
you can also add lights and use a negative intensity to create dark light in your scene

First year 3D Grad

Last edited by Turbo Dan; 10-03-2005 at 03:29 AM.

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# 3 10-03-2005 , 06:53 AM

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I changed the key light to 2 spotlights and set the decay rate to linear. I also toned down the diffuse color on the table. Though it seems that the shadows around the light fixture seem a little sharper and fake. What do you think?

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# 4 10-03-2005 , 07:08 AM

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I agree with Turbo Dan. I would use more decay on your primary light from the lamp. Dont worry too much about getting the whole room lit with just one light. Just worry about getting the main source of light to look like its actually emitting light. Stay away from making the light too intense at first. Try Changing your main light to use a quadratic decay rate with a high intensity of around 1000-2000 to start out with. Once you get your main light set up, then you can go back and add many small point lights with no shadows to make everything else in the scene show up.

If you really want to make things look neat, you can somewhat fake GI by using one main source light w shadows (I prefer raytrace) and a bunch of point lights with depth map shadows enabled. Depth map shadows by default emmits 6 different shadows maps in each axis. You can use this to your advantage by only allowing shadows to project in only a few axis. This way you can essentially surround the source light with a bunch of point lights and only enable the d-map shadows to project in the direction that the source light is being cast.

So for example if you were to create a spot light pointing in the +Z axis, the point light in front of the spot light would only have d-map shadows enabled on the +Z axis and maybe the + or - Y axis depending on the angle of the spot light. You can get some very realistic effects by using this technique. If you want to try this, just remember to make all the point lights use a quadratic decay and relatively low intensity.

If you have any questions about this let me know.

Here is what I created using this technique:

user added image

We perceive the world not as it really is, but as it is useful for us to perceive.

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# 5 10-03-2005 , 03:47 PM

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you could maybe try to turn up the transluscence on your lampshade material so that it doesn't cast much of a shadow.. just a thought

First year 3D Grad

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# 6 10-03-2005 , 04:14 PM

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Morg002,

I tried following your advice by first starting with the main source light and setting the decay rate to "Quadratic" and the intensity between 1000-2000.

well here is a render with decay rate set to "Quadratic" and I started with the intensity set to 1000. So I really don't know what your talking about and I could never get good results with decay rate to start with.

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# 7 10-03-2005 , 04:15 PM

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Originally posted by Turbo Dan
you could maybe try to turn up the transluscence on your lampshade material so that it doesn't cast much of a shadow.. just a thought

Originally Posted by

Turbo Dan,
I appoligize, I didn't see your last post at first. Though thats an idea.

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# 8 10-03-2005 , 05:17 PM

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Originally posted by junkyBob
Morg002,

I tried following your advice by first starting with the main source light and setting the decay rate to "Quadratic" and the intensity between 1000-2000.

well here is a render with decay rate set to "Quadratic" and I started with the intensity set to 1000. So I really don't know what your talking about and I could never get good results with decay rate to start with.

Originally Posted by

Hehe...Sorry. I guess it really depends on how big your scene is. Thats obviously way too much light for such a small room. Just keep playing with the lighting untill you can get the primary light to not be so bright and blown out. One thing that you might try is to group all the objects in the room and scale them up. That way a quadratic light set to an intensity of around 1000 wont be quite so bright because it has more space for the light to spread around.
Given the size of your scene right now I would say that you would need to change the light settings in the low 100s. But I would really suggest grouping all objects (not the lights) and enlarging it by at least twice as much. After the room is larger, then play with the lighting. Try this and I am sure you will get better results. Hope that helps...

We perceive the world not as it really is, but as it is useful for us to perceive.

Last edited by morg002; 10-03-2005 at 05:28 PM.

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# 9 10-03-2005 , 06:10 PM

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Originally posted by morg002
Hehe...Sorry. I guess it really depends on how big your scene is. Thats obviously way too much light for such a small room. Just keep playing with the lighting untill you can get the primary light to not be so bright and blown out. One thing that you might try is to group everything in the room and scale it up just a bit. That way a quadratic light set to an intensity of around 1000 wont be quite so bright because it has more space for the light to spread around.
Given the size of your scene right now I would say that you would need to change the light settings in the low 100s. But I would really suggest grouping everything and enlarging it by at least twice as much and then play with the lighting. Try this and I am sure you will get better results. Hope that helps...

Originally Posted by

I figured that seemed awfully high. Though I have to agree on size counts. My room is 16 units wide and 19 unit in depth and 6 units in height. I was thinking on the concept 1 unit = 1 foot in the width and depth, and .75 of a unit = 1 foot in height. I did it this way because if I did 1 unit = 1 foot in all axises, the camera view looks like the room is really small. Though finding that making the height smaller makes the room appear larger. I was going to ask your guys opinion on that too later on.

Anywho,
The picture below is an update and here is what I did. First off I used a total of 6 point lights and 1 directional light. The first point light is the key light placed inside the lampshade and the intensitiy was set to 5 with a decay rate set to quadratic and used depth map shadows. The second point I placed below the lamp shade and set its' intensity to 5 and decay rate to quadratic as well but I didn't use any shadows. The third light was placed inside the floor near the lamp with its' inensity set to .5. This helped fill lamp area and flatten the sharp glow in the ceiling that the lamp shade light created. The fourth light was placed on the ceiling above the lamp with its' intensity set to .5 no decay rate and depth map shadows turned on. This help create more shadows around the room. The fith point light was positioned in the back wall with it's intensity set to .5 as well and no decay rate and no shadows. This helped fill in the space between the 2 walls and balance out the ceiling. And the last point light was placed on the floor near the desk. This in my opinion created a slower fade in the back wall and gave a little more detail to the desk. As for the directional light was for in my opinion the floor needed some help.

So all in all, I am once asking again your opions, please user added image

... and BTW I will be glad to post my file for anyone who wishes to help pointing me in the right direction.

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# 10 10-03-2005 , 06:19 PM

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Originally posted by junkyBob
I figured that seemed awfully high. Though I have to agree on size counts. My room is 16 units wide and 19 unit in depth and 6 units in height. I was thinking on the concept 1 unit = 1 foot in the width and depth, and .75 of a unit = 1 foot in height. I did it this way because if I did 1 unit = 1 foot in all axises, the camera view looks like the room is really small. Though finding that making the height smaller makes the room appear larger. I was going to ask your guys opinion on that too later on.

Originally Posted by

If you need to correct this you can change your camera focal length settings to make the room look larger or smaller.